SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53eb47c94219c0ee283e15da8ef064a24575bb381bddbf5c8247a4d6b7b91b2c' 
  AND token = 'vYmtaLB03lmgppy6uwjj3kr3NBj6/2Gj3Okmmih0GiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables